Not Applicable
The present invention is related to the field of agro-products, pharmaceutical production and sample analysis.
In the field of sample analysis, a large variety of studies are conducted in order to monitor for the presence of contaminants in food. In particular, toxins such as brominated and chlorinated pesticides, PCBs, and dioxins are extracted, purified and fractionated from pharmaceutical, environmental and biological samples. New and more stringent regulations regarding acceptable levels of these contaminants are continuously being adopted by the government or other regulatory agencies, driving the development of analytical systems that are more reliable and commercially practical. Important criteria in the development of such systems are the detection of more compounds, with lower detection limits, fast turn around and the ability to process a large number of samples efficiently. Currently, only a few laboratories can fulfill these emerging requirements.
Since chlorinated and brominated compounds are very toxic at sub-ppt (part per trillion) and ppqt (part per quadtrillion) levels, the purification of these compounds becomes a difficult task in sample analysis. It is necessary, for example, to protect the sample from interfering compounds during the extraction, purification and fractionation processes. Interfering compounds can be introduced from the air and surrounding environment.
For example, it is required to detect some PCBs in low ppt level in food samples. However, the amount of PCBs in the air and other surroundings of laboratories may exceed the detection limits of the sample, so that the laboratories are unable to perform accurate testing. As a result, lab testing facilities are forced to construct new clean room labs with controlled environments. Therefore, testing for these highly toxic compounds in food is becoming very difficult, and few labs are able to perform this testing.
In the field of agro-products, extracted, purified and separated end products are obtained from spices, herbs, aromatic plants, and medicinal plants and are used for various end use applications such as cosmetics, flavors, medicines, perfumes, etc.
In the field of pharmaceutical production, compounds of interest are extracted, purified and separated for use in producing drugs and supplements. These processes are similar to those used in sample analysis, although they are usually carried out on a much larger scale to provide a desired amount of product.
For several years, new extraction techniques have emerged that exhibit advantages such as lower solvent consumption, suitability for automation and higher throughput for processing solid and semi-solid samples such as food samples. The purification or xe2x80x9cclean-upxe2x80x9d step has also evolved from the early use of semi-automated stages to more recent use of entirely automated systems suitable for preparing a large number of samples. Nevertheless, there is a continuing need for fast, efficient systems for performing high-quality sample analysis and pharmaceutical production.
In accordance with the present invention, a system is disclosed for pressurized liquid extraction and purification of solid biological materials (also referred to herein as xe2x80x9csamples) containing trace substances that may be the subject of subsequent analysis or that may be used as an ingredient in a pharmaceutical product. The system may be used, for example, in the extraction, purification and fractionation of trace substances such as chlorinated pesticides, PCBs, pesticides and brominated compounds.
Extraction, purification and fractionation are performed in a closed loop system, which reduces the exposure of the sample to the air and surrounding environment. In the case of sample analysis, hundreds of toxins such as dioxins, PCBs and pesticides can be detected at low levels in a single run at generally high speed. High-quality food sample analysis can therefore be performed, which is required to protect the population from contaminants from a variety of sources, such as agricultural and environmental sources or from terrorist activities.
The disclosed system employs an integrated extraction, purification and fractionation system for detection of toxins at levels as low as ppqt in a closed loop system. The system includes a pressurized liquid extraction (PLE) module that includes a solvent selection valve, a PLE cell, a heating element thermally coupled to the PLE cell with over temperature shutoff, a high-pressure pump coupled to an input port of the PLE cell, and a pressure regulator coupled between an output port of the PLE cell and an input port of a cooling coil. The output port of the cooling coil is connected to the output port of the PLE module. The cooling coil conditions the temperature of the extract and transfers the cooled extract to the input of a purification module. The PLE module continuously performs high-pressure, high-temperature extraction on the solid sample to yield liquid sample, and concurrently provides the liquid sample to the output port of the PLE module.
The system further includes a purification module having a sample input port coupled to the output port of the PLE module. The purification module operates concurrently with the extraction of the liquid sample by the PLE module to separate a purified liquid sub-sample from the liquid sample and to fractionate chlorinated dioxins, PCBs, pesticides, and brominated compounds. The fractionated sub-samples contains all or nearly all of the trace substance present in the solid sample. The purified fractions are concentrated in a concentration assembly and can be utilized in subsequent analysis to determine the concentration of hundreds of targeted trace substances in the sample.
The system provides rapid detection of hundreds of the most toxic compounds in food. In addition, it minimizes the need for giant clean room labs which otherwise might be necessary to perform testing and detection of those toxins. The system also simplifies sample handling inside the laboratory and can reduce sample preparation time to less than two hours. Finally, the system can accommodate many types of solid matrices, including those that must be processed in large quantities.
Other aspects, features, and advantages of the present invention will be apparent from the Detailed Description that follows.